Armature with no deformation?
Here's how to set up what I think you want to set up.  (I used 2.82 Alpha, but it should work on any >=2.80).

Start with an empty scene.  Add an armature consisting of a single "Bone".  In edit mode, extrude a second "Bone.001" from the tip, and extrude a third "Bone.002" from its tip.  Switch to object mode, and add your spheres.  In wireframe, it should look like this:



Now, LMB select the bottom sphere and Shift-LMB select the armature.  Ctrl-Tab switch to Pose mode, click the bottom bone.  It should look exactly like this, with the bottom sphere as the secondary selection (dark orange) and the bottom bone in the armature selected (light blue):



Finally, Ctrl-P Set Parent to Bone.

To parent the second sphere, Ctrl-Tab back to object mode, LMB select the middle sphere, Shift-LMB select the armature, Ctrl-Tab switch to Pose mode, click the middle "Bone.001", and Ctrl-P Set Parent to Bone.

For the final sphere, Ctrl-Tab back to object mode, LMB select the top sphere, Shift-LMB select the armature, Ctrl-Tab switch to Pose mode, click the top "Bone.002", and Ctrl-P Set Parent to Bone.

You should now have each sphere parented to a single armature bone, using Bone Parenting.  In pose mode, each bone should control one sphere with no deformation of the other spheres.  Here's the blend file: